Spanner bars and other secondary support structures are commonly used in commercial aircraft for wire bundle management. A typical spanner bar includes a thin gauge member having a repeating pattern of mounting holes separated by lands.
The spanner bars may be secured to primary aircraft structures. Wire support hardware such as p-clamps and ring posts are fastened to the spanner bars, and wire bundles are secured to the wire support hardware.
A ring post may be fastened to a spanner bar as follows. The ring post is positioned on a front side of the spanner bar. A threaded end of the ring post is aligned with a select open hole of the spanner bar. The threaded end of the ring post is maneuvered through the select hole until threads are exposed on a back side of the spanner bar. A loose washer and nut are placed over and threaded onto the threaded end of the ring post. The nut is tightened with a hand tool until firmly clamped against the spanner bar. This process is repeated for each ring post.
It would be desirable to reduce part count and installation time of attaching wire support hardware to a spanner bar. Even a seemingly trivial reduction for a single nut and washer can be significant due to the large number of fastening operations on secondary support structures in a commercial aircraft.
According to an embodiment herein, an aircraft comprises a secondary support structure, and a nut plate engaging the secondary support structure. The nut plate includes at least one locator protrusion engaging a mounting hole in the secondary support structure to constrain motion of the nut plate along the secondary support structure. The nut plate further includes means for additionally constraining motion of the nut plate away from the secondary support structure.
According to another embodiment herein, an apparatus comprises a spanner bar having a surface with an alternating pattern of mounting holes and lands, and a nut plate engaging the spanner bar. The nut plate includes a body having a mounting surface and an internally threaded bore accessible from the mounting surface, the mounting surface in contact with the spanner bar; at least one protrusion extending from the mounting surface, each protrusion engaging one of the mounting holes to constrain motion of the nut plate along the spanner bar; and means for engaging the spanner bar to constrain motion of the nut plate away from the spanner bar without cooperation of mounting hardware.
According to another embodiment herein, a nut plate is configured to engage a thin gauge member whose base has a pattern of equidistant holes and lands. The nut plate includes a body having a mounting surface and an internally threaded bore accessible from the mounting surface; a locator protrusion configured to extend from the mounting surface and into one of the mounting holes; and first and second resilient finger tabs cantilevered to the body and extending outward from the body. The tabs are configured to releasably engage the member's return flanges to constrain motion of the nut plate away from the base.
These features and functions may be achieved independently in various embodiments or may be combined in other embodiments. Further details of the embodiments can be seen with reference to the following description and drawings.